A Program of Graphic Computing, developed in the Language of Programming AUTOLISP and run in AUTOCAD 2000, which is guided toward the Investigation in Bioclimatic Architecture, is presented. Before a model of solar protection in 3D, and loading the input data of the geographical localization and orientation, time and evaluation date (chosen by the user), the program calculates and projects the simulation of the corresponding shade contours on every plane that constitutes the 3D pattern (openings, walls, protections, floor...). In this research different areas of knowledge concur: Plane and spherical trigonometry applied to the solar ray and to the Bioclimatic Architecture, space geometry, plane graphical representation of three-dimensional objects, a concept of the transformation of vision for the three-dimensional representation of the objects in computers, and modern programming techniques.